In order to broaden findings beyond high-income countries, this study used path models to test associations between parent involvement and student achievement in Brazil using a 2017 census of public school students in fifth grade (N = 2,167,729, M[subscript age] = 11, 49 % female, 44% "Parda," 29% White, 11% Black, 3% Asian, 3% Indigenous) and ninth grade (N = 1,782,899, M[subscript age] = 15, 51% female, 46% "Parda," 29% White, 12% Black, 4% Asian, 3% Indigenous). Parent involvement showed positive associations with student reading and math achievement for fifth graders ([beta]s = 0.11 & 0.09) but essentially null associations for ninth graders ([beta]s = -0.01). Students' homework completion mediated associations in both grades ([beta]s = 0.03). Parent education was not a strong moderator of associations.